Trend Analysis of Flipped-Classroom Research in English as A Foreign Language

The researchers accessed the online Scopus database to gather data for the study. The researchers utilized Microsoft Excel for frequency analysis, VOSviewer for data visualization, and Harzing's Publish or Perish for citation metrics and analysis. According to a keywords search for "Flipped-Classroom” and “EFL," 26 articles were assessed. The research on this matter was started in 2014 with one article for the entire year. From the next year to 2020, the number of publications each year grew. As a result of the analysis, the researcher discloses the data on the growth of the research, the most active journals on the topic, the distribution of author keywords and co-occurrences of author keywords, and the most active authors and authors’ collaboration. It was shown that throughout the last seven years, researchers have increased their focus on flipped classroom and EFL research, with the highest number of publications occurring in 2020 (11 papers). The most active journal on the subject is the International Journal of Emerging Technologies in Learning, which has published three pieces on the subject. Additionally, the investigation found that instruction, perception, and performance are the most commonly used keywords. However, involvement and motivation are mentioned infrequently in research reports.


INTRODUCTION
The advancement of technology requires improvement in teaching and learning activities. Electronic devices and media cannot be separated from human daily life. Innovations are needed to accommodate electronic devices and media into the teaching and learning activities. Bergmann and Sams explored the classroom concept to answer the challenges in 2007. Initially, they employed the lecture technique to teach students math and science subjects. He made an explanatory video, which kids may view at home to learn. On the following day, the teacher assisted the students to complete assignments in the classroom (Bergmann & Sams, 2012). The Flipped Classroom Model refers to the home-completed assignments as the model's original principle.
Unlike traditional classrooms, the flipped classroom flips the whole classroom or assignment by using technology, allowing for greater participation in the classroom (Overmyer, 2012). It restructures the duration of learning, either outside or inside the classroom. The model flips learning approaches by giving lessons to be done outside the classroom and bringing assignments to the class. The flipped classroom is an instructional strategy that incorporates two critical components: the utilization of computer technology and the incorporation of interactive learning activities (Hsieh et al., 2015). This model is especially compatible with the recent phenomena since students utilize electronic devices on daily basis. Online learning enables students and lecturers to be connected through technology to mediate the learning activities (Syahraini et al., 2022) and achieve optimum learning achievement since learning achievement could be a determining factor to see students' success in learning (Radyuli & Aska, 2019).
Flipped-classroom is a model that is compatible to be applied in various subjects. Several researchers conducted studies to see the model's effectiveness (Li & Suwanthep, 2017) and benefits (Chuang, 2018). Unfortunately, little information could be obtained regarding the topics. Therefore, this research intended to overcome the sates limitation through scholarly networks and worldwide trends investigations involving flipped classroom and ELT on articles published between 2014 and 2020. The researcher focused his analysis on the most popular journals on the topic, the growth of the research, the distribution and co-occurrences of author keywords, the distribution of publications by country, authors' collaboration, the most active authors, and co-authorship distribution.
Bibliometrics is a statistical examination of publications like published articles (Ding et al., 2016). The data may be found by browsing journal databases. Researchers perform this analysis on publication and citation to analyze authors, generate concept maps, and scientific domain changes (Massimo & Cuccurullo, 2017). A distance-based map and a graph-based map are produced by this analysis. Researchers, research groups, and research organizations can benefit from the bibliometric analysis since it provides an overview of their scientific production and the citations to this work.
In order to produce and display bibliometric maps, the VOS (Visualization of Similarities) viewer was created. Graphics is a key component of VOS. VOSviewer is capable of displaying massive bibliometric maps. It produces authors or journals maps based on keywords and co-citation data. VOSviewer can track more than 100 search results. Informative maps can be produced by the VOS mapping technology which is fully incorporated into VOSviewer. It shows three different sorts of visualizations: a network, an overlay, and a density (Van Eck & Waltman, 2020). In this research, the researcher only utilized the network visualization of articles found on the Scopus database.
Several other researchers have conducted Bibliometric analysis on flipped-classroom. Researches have been conducted to identify and analyze articles on the flipped classroom model brought by well-known journals between 2010 and 2019. It was found that ten journals published eighty-eight articles by 2019 and three frequently used author keywords are flipped classroom, active learning, and blended learning (Julia et

Evaluation
Evaluating key results al., 2020). The novelty of this research lies in the specified topic of discussion. Unlike the previous research, this research tried to analyze the flipped classroom in a specific context, namely English as a Foreign Language (EFL), which has never been conducted before.

METHOD
The bibliometric analysis is employed to achieve the goals stated in the introduction. It is a statistical examination of published articles (Ding et al., 2016). It entails the use of statistical tools to determine qualitative and quantitative changes within a certain scientific research topic in order to determine the publishing profile of that topic and identify trends within a field. In order to better utilize, organize, and decipher data in a certain area of study, bibliometric analyses look at a variety of bibliographical sources (Merigó et al., 2015). Detailed information could be obtained through this analysis such as the keywords frequency, citations, and authors within different time frames (Rusly et al., 2019). The frequency of keywords, citations, and authors may be used to analyze data on publications across time.
Using the Scopus database and Scopus indexed material, 26 articles were retrieved for this study. The researchers selected the Scopus database as the source of data collection. "Flipped-classroom" and "EFL" were the keywords searched for the analysis. The research topics will be answered using network visualization and bibliometric indicators.
People, theories, and organizations are all linked together in Scopus thanks to the meticulously crafted original information. Scopus generates precise citation results and detailed profiles of researchers via the use of sophisticated tools and analytics. Search terms for titles, abstracts, and keywords were included. The analyzed documents were published between 2014 and 2020. In this research, the researchers employed the bibliometric analysis procedure proposed by (Zarea et al., 2017).

Figure 1. The Bibliometric Analysis Procedure
The researchers searched the predetermined keywords into the Scopus database. The researchers limited the keywords into "flipped classroom" and "EFL" to gain more comprehensible data output. Without the limitation, the obtained data would be too broad and come from a variety of disciplines. Besides, the researcher also limited the publication time frame. Originally, the time frames were limited to ten years of publication, specifically 2011 to 2020. However, the first articles on the focused topics were first published in 2014. Thus, the analyzed articles were those published from 2014 to 2020 (seven years).
26 articles were evaluated based on the keywords input into the search section of the Scopus database. The data was extracted into RIS and CSV formats. MS Excel, VOSviewer, and Publish and Perish. MS. Excel was used to compute the publishing frequency and create the necessary graphical data. Furthermore, the bibliometric networks were visualized using VOSviewer version 16.17.

RESULTS AND DISCUSSION
The analysis of the 26 selected articles reveals the data on the growth of the research, the most active journals on the topic, the spread and co-occurrences of author keywords, and the most active authors and authors' collaboration.

Research Growth
The researcher tracked the research patterns and growth by looking at articles' publication years (Ahmi & Mohamad, 2019). The research growth was quite dynamic. There were 26 articles published by several journals over the eight years. The first identified article was published in 2014, which also conclude the publications at that year. Unfortunately, within two years, no research was published on this topic. Therefore, there were two years of the void with no published articles regarding flipped-classroom and EFL. In the following year, the research regarding this topic significantly rose which reached the highest number of the publication since the first identified publication. There were eight articles published in 2017. The number of publications unexpectedly decreased in 2018. At that year, only two articles were published. In 2019, although not significant, the number of publications rose to four published research articles. The year 2020 was marked as the overall highest published article within the specified time frame. There were eleven articles published that year. The detailed data on the number of publications can be seen in Table 1 and Figure 2.  Co-occurrence analysis was done to identify the terms with VOSviewer. The analysis revealed that there are three clusters formed. Based on the extracted bibliographic data, full counts had been performed resulted in fifteen keywords and three clusters. The first cluster consisted of six items, namely "class activity", "effectiveness", flipped-classroom approach", "implementation", "performance", and "video". The second cluster consisted of five items, namely "case study", "experience", "perception", "technology, and "use". The last cluster consisted of items, namely "EFL context", "Engagement", "Instruction", and "motivation".

Figure 3. Network Visualization of Co-occurrence by Author Keywords
According to Figure 3, the commonly used terms were instruction, perception, and performance. However, involvement and motivation are only mentioned in a few study publications. This discovery provides an opportunity for further scholars to investigate infrequently mentioned issues.

The List of Authors
The analysis revealed that there are 26 Scopus-indexed articles between 2014 and 2020. The detailed list of the articles and other supporting information is contained in Table 4.  (Fitriana et al., 2020) The flipped English classroom in EFL context: A study of education 4.0 International Journal of Advanced Science and Technology 17 (Hu & Hsu, 2018) The value of adding a flipped learning component to a humanities course in higher education: Student perception and performance  (Zou, 2020) Gamified flipped EFL classroom for primary education: student and teacher perceptions Journal of Computers in Education 24 (Ghufron & Nurdianingsih, 2020) Flipped teaching with call media in EFL writing course: Indonesian EFL writing teachers' reflection Pertanika Journal of Social Sciences and Humanities 25 (Lakarnchua et al., 2020) Insights from the implementation of a flipped classroom approach with the use of a commercial learning management system

Number of Authors per Document
The researcher performed a descriptive analysis to investigate the authors' aspect. Besides, the researcher calculated the frequency and percentage. Most of the publications are written by only one author (38 %), followed by three authors (35%) and two authors (27%) per document. Table displays the data on the numbers of author per document.

Figure 4. The Network Visualization of Co-authorship
The visualization only displays one cluster because only the three displayed authors who have collaborated to write articles on flipped-classroom on EFL. The network only displays three authors who have collaborated in writing more than one research on flipped-classroom on EFL.
This research results are supported by a bibliometric analysis conducted by Tsai & Wu (2020). They found that there are 645 articles focused on flipped-classroom across multiple disciplines based on data taken from Web of Science. Furthermore, they found that there are 24 highly-cited articles with the most frequent keywords being the overall feasibility of the flipped classroom course design and practical model, and students' performances, and student-regulated learning (active learning and readiness) outcomes. Another bibliometric study on flipped-classroom and English language teaching has been conducted that resulted that the most frequent keyword of achievement and evaluation strategy ‫الشبيبية(‬ & Al-Ayasra, 2019). The study also results reveal that the flipped classroom can provide students with a more interactive environment that will lead to higher learning achievement and better preparation for 21st-century learning and work environments.
The results of previous studies can be used to broaden the finding of this research, especially in enriching the keywords findings. The studies reveal that besides the instruction, perception, and performance as the finding of this research, other keywords such as achievement, evaluation strategy, course design, practical model, students' performances, and student-regulated learning have been frequently researched. This information can serve as guidance for further researchers to find other themes in researching flippedclassroom.
The finding of this research can assist further researchers in selecting the topic of their research, especially research related to flipped-classroom. The most frequently occurring keywords mean that the topics related to those keywords have been researched previously. Thus, further researchers can find other alternatives to focus their research. However, this research is still limited to only one data source, namely the Scopus database. Different results ought to be generated if the research incorporates multiple data sources.

CONCLUSION
In this age of modern technology, the flipped classroom on EFL is surely rising and gaining popularity. This research plays a role in enriching the corpus of knowledge by reporting the findings of a study of academic networks and global research trends on Flipped-classroom instruction in English as a Foreign Language. The researcher extracted bibliometric data for 26 research papers from the Scopus database using the keywords "flipped-classroom" and "EFL." It was shown that throughout the last seven years, researchers have increased their focus on flipped classrooms and EFL research. The most frequent publications occurred in 2020 (11 papers). The most active journal on the subject is the International Journal of Emerging Technologies in Learning, which has published three pieces on the subject. Additionally, the investigation found that instruction, perception, and performance are the most commonly used keywords. However, involvement and motivation are mentioned infrequently in research reports. This discovery paves the way for future academics to investigate little-discussed subjects. The findings of this bibliometric analysis may act as a spur for more research on flipped classrooms on EFL and may contribute to its broad adoption.